After innervating the sternocleidomastoid muscle, the spinal accessory nerve emerges and down crosses the posterior cervical triangle to innervate the trapezius. At the posterior triangle, the nerve is closely related to local lymph nodes and may be injured by their enlargement or surgical removal. Injury to this nerve is uncommom. Most cases are iatrogenically due to surgical procedures in the posterior cervical triangle, often following lymph nodes biopsies or benign turmors approaches. We present seven cases of post-surgical related spinal accessory nerve injury and discuss its clinical and electrophysiologycal profiles. The major motor signs were shoulder drop and paresis to raise arm. Pain and sensory complaints were almost universal and most probably due to concomitant injury of cervical plexus cutaneous branches, which are in direct relation to the spinal accessory nerve in the posterior cervical triangle. Lesion type is usually axonotmesis, but varied degrees of compression by cicatricial spurs are observed in some patients. Surgical approach and nerve repair must be considered for pacients with delayed recovery.
spinal accessory nerve; nerve injury; electrophysiology; quantitative electromyography; neck surgery; posterior cervical triangle
